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GULEA, Aurelian; GRADISTEANU, Maria; USATAIA, Irina; TSAPKOV, Victor; GRAUR, Vasile; CHUMAKOV, Yurii; PETRENKO, Peter A.. Coordination compounds of some 3D metals with salicylidene-4-allyl-s-benzylisothiosemicarbazide. In: Achievements and perspectives of modern chemistry. 9-11 octombrie 2019, Chişinău. Chisinau, Republic of Moldova: Tipografia Academiei de Ştiinţe a Moldovei, 2019, p. 151. ISBN 978-9975-62-428-2.
|Achievements and perspectives of modern chemistry 2019|
Conferința "International Conference "Achievements and perspectives of modern chemistry"" |
Chişinău, Moldova, 9-11 octombrie 2019
S-Alkylisothiosemicarbazones belong to an important class of thiosemicarbazone derivatives. Much attention has been paid to the synthesis, structure and biological properties of coordination compounds with these ligands. The aim of this work is the synthesis of copper(II), cobalt(III) and iron(III) coordination compounds with salicylaldehyde 4-allyl-S-benzylisothiosemicarbazone (HL), determination of their composition, structure, and physicochemical properties. Isothiosemicarbazone HL was synthesized by reaction between 4allylthiosemicarbazide and benzyl chloride upon heating for 8 hours. After that, salicylaldehyde was added to the reaction mixture. In the final step, the obtained hydrochloride of salicylaldehyde 4-allyl-Sbenzylisothiosemicarbazone was neutralized using potassium hydroxide. m.p. (HL) = 63-65 0C. The structure and purity of the synthesized isothiosemicarbazone HL was confirmed using 1H, 13C NMR spectroscopy and also X-ray analysis. All peaks in the spectra of isothiosemicarbazone HL are double. It indicates the presence of tautomeric forms of isothiosemicarbazone in solution. The experiments showed that ethanolic solutions of copper(II) chloride, bromide, nitrate and acetate react with salicylidene-4-allyl-S-benzylisothiosemicarbazide (HL) in the molar ratio of the 1:1, forming colored microcrystalline substances. In the case of iron chloride and bromide and cobalt chloride, the reaction takes place in a molar ratio of 1:2. The molar conductivity values in methanolic solutions show that all synthesized coordination compounds represent 1:1 electrolytes. The analysis of IR spectra has shown that isothiosemicarbazone HL coordinates to the central atoms by deprotonated phenolic oxygen atom and azomethine and thiocarbamide nitrogen atoms. The structure of the complex [Fe(L)2]Br was confirmed using X-ray analysis. This compound has a distorted octahedral structure. The isothosemicarbazone behaves as an O, N, N tridentate monodeprotonated ligand and forms five- and six-membered metallocycles. A bromide ion is in outer sphere. The sulfur atom does not participate in the formation of bonds with the central atom.